Steam-boiler



(No Model.) 2 Sheets-Sheet 1. EL G. SHORTT. STEAM BOILER.

No. 470,631. Patented Maf.

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` UNITED STATES `PATENT Fries.

EDWARD G. SHORTT, OF CARTHAGE, ASSIGNOR OF ONE-HALF TO CHARLES G. EMERY,OF BROOKLYN, NEW-YORK.

STEAM-BOILER.

SPECIFICATION forming part of Letters Patent No. 470,631, dated March 8,1892. Applicationiiled October 21, 1891l Serial No. 409,400. (No model.)

To all whom t may concern: t

Be it known that I, EDWARD G. SHORTT, a citizen of the United States,residing at Carthage, in the county of Jefferson and State of New York,have invented new and useful Improvements in Steam-Boilers, of which thefollowing is a specification.

My invention is designed to supply certain improvements insteam-boilers, whereby a 1o more perfect combustion shall be obtainedwithin the furnace and whereby, also, the wall of the tire-pot shall beprevented from burning, and a perfect or nearly-perfect consumption ofthe products of combustion effected to increase the heat, economize thefuel, and render the furnace as nearly smokeless as possible.

To these ends my invention involves the features of construction and thecombination .2o or arrangement of devices hereinafter described andclaimed.

To enable others skilled in the art to understand and to make,construct, and use my said invention, I will describe the same indetail, reference being had to the accompanying drawings, iu which-Figure 1 is a central vertical section of an upright boiler having myinvention incorporated. Fig. 2 is a horizontal section on the 3o line 22, Fig. 1. Fig. 3 is a horizontal'seetio'n upon the line 3 3, Fig. 1.

In the said drawings the reference-numeral 1 denotes the steam-boilerand furnace, which in this instance are united in one structure,

the steam-boiler consisting of an outer and inner sheet 2 and 3inclosing a water and steam space, which is annular in horizontalsection. The inner sheet 3 is bent outwardly at its upper and lower endsto unite with the 4o outer sheet, which is cylindrical throughout, andto afford the annular water-space between the two. The boiler isinclosed` by a jacket 4 to prevent loss of heat by radiation andconduction, and the space between the outer sheet 2 and jacket 4 isfilled with an asbestus packing. The boiler is supported upon a base 5of any suitable construction, and within this base is arranged theireepot, which is composed of an open ring 7, having upon 5o its loweredge an inner and outer iia'nge 9 and 10, respectively, the outer angeresting on bracket-lugs 12, projecting from the base, and being providedwith openings 13 for air to sustain combustion. The inner Iiange 10supports the grate 14. An air-space for draft is allowed extendingentirely around the firepot between the outwardly-detiected lower end ofthe inner sheet 3 of the boiler and the outer face and upper edge of thering 7. The

`air entering by way ot' said space impinges 6o upon the inclinedannular surface 15 ot" the inner sheet 3, which overhangs the ring 7,and will be somewhat deflect-ed thereby toward the center of thecombustion-chamber,which lies above the fire-pot and is bounded orinclosed by the boiler. A cap 16 surmounts the latter and conducts theproducts of combustion to the stack 17. Byconstructing the inner shell 3with the annular outwardly curved or bent portion 15 at its lower endportion to overhang 7o the upper edge of the grate-ring 7 the ascendingair-currents are deiiected inwardly, so that the heat is concentratedand intensified at the center, where it strikes the lowermost watertubes18. The portions 15 also prevent the 75 air-currents risingperpendicularly along the inner sheet, which would tend to cool theboiler, while by throwing the air-currents laterally they at once minglewith the products of combustion and greatly intensify the heat 8o whereit strikes the lower water-tubes.

The heating and water space of the boiler is largely increased by meansof water-tubes 18, projecting laterally from the inner sheet of theboiler toward the center of the combustion-chamber. These tubes areusually arranged in spiral order to give the most advantageous contactto the ascending heated gases, though I may use any construction adaptedto accomplish the same end. These 9o tubes are of the constructionshown, described, and claimed in the Letters Patent granted to me the24th day of February, 1891, No. 447,209.

The reference-numeral 19 indicates thelivesteampipeof-theboiler,whicl1enters thesteam- 9 5 space immediatelybeneath the line of union of the inner and outer sheets at the upper endof the boiler. Beneath this pipe is inserted an annular water-bathe orbaffling-plate 20, which extends entirely around through the rocstea1n-space and has its edges abutting against the inner faces of thesheets inclosing said space. This ring is supported upon pins 2l, whichare either' tapped or driven through openings in one of theboiler-sheets and project into the steam-space. Perforations 22 areprovided in the baffling-plate at suitable intervals to allow the freepassage of steam,but of such size and frequency as to practically cutoff the passage of any material quantity of water'which may be dashedagainst the plate by the violent ebullition within the boiler.

The construction of the boiler and the form and arrangement of theseveral parts may be considerably varied without departing from myinvention. It is evident,- also, that the baffling-plate may be used inother types of steam-boiler and may be of other than annular form.Besides preventing the water from being dashed over the mouthv of thesteampipe I9 and driven into it by the flow of steam, this plate draftsthe steam from all parts of the steam-space below it with substantialuniformity and aids 4in preserving it at a point somewhat abovesaturation.

The inner and outer sheets of the boiler, which are in the presentinstance substantially cylindrical and concentric, are formed of steel,and each sheet is lap-welded throughout the entire height of the boiler,the weld being so formed that there is no perceptible differenceinthickness or in the homogeneity of the metal as compared with otherparts. I have indicated this weld in the horizontal section, Fig. l, bya dotted line at 23; but it will be understood of course that inpractice the only means of detecting the weld is bythe entire absence ofrivets, there being no external indication thereof. I thus obtain aboiler which is of uniform strength in every part. Instead of cuttingaway a very considerable part of the metal to admit the line of therivets usually employed, I preserve the boilersheets intact and am ableto employ high pressures without the danger so Well known in rivetedboilers of the sheet tearing along the line of rivets.

By combining the external draft between the boiler and fire-pot with thedraft passing directly through the grate I am able to effect a completeconsumption of the products of combustion and produce avery intenseheat, beside utilizing all the heating capacity of the fuel, and thusinsuring the utmost practical economy. In burning soft coal, forexample, the interior draft or that passing through the grate and insidethe fire-pot is wholly insufficient to sustain perfect combustion abovethe grate. The quantity of carbonio-acid gas given off and theabsorption and consumption of oxygen in effecting the primary combustioncauses the evolution of a dense smoke in great volumes containing themost valuable constituents of the fuel. The external draft, which isslightly deflected inward, mingles with these products of the primarycombustion and furnishes sufficient oxygen to maintain completeconsumption andproduce an intense heat, giving an extremely rapid steamgeneration. The air entering between the fire-pot and boiler not onlyprevents the fire-pot from burning, but the air itself is heatedsufficiently by surface contact with the lower end of the boiler tosustain the secondary combustion perfectly and avoid chilling theinflammable gases.

I am aware that heretofore a furnace has been used having a draft-spaceexternal to the nre-pot, and I do not claim such an invention.

I am also aware that boiler-plates have been built up or composed offractional parts welded to each other, the plate thus formed beingunited to other plates by rivets.

What I claim is- 1. The combination, with an upright steamboiler havingits inner sheet formed with an annular outwardly curved portion at thelower end, of the grate-ring 7 ,having its lower edge formed with aninner grate-supporting flange 10 and an outer perforated iiange 9 forthe upward passage of air, and a grate resting upon the grate-supportingflange, substantially as described.

2. The combination of a base 5, having brackets or lugs I2, and a boilersupported by the base and having an annular outwardly-curved portion 15at its lower end, of a grate-supporting ring 7, located under theannular curved portion and formed at its base with an innergrate-supporting fiange I0 and an outer perforated ange 9 for the upwardpassage of air, and a grate resting upon the grate-supporting flange,substantially as described.

3. The combination, with a base 5, of a boiler having its inner sheet 3provided with vlaterally projecting water tubes 18 and formed at itslower end with an annular outwardly-curved portion 15, a grate-ring 7,arranged under the outwardly-curved portion and formed at its base withan inner gratesupporting flange l0 and an outer perforated ring 9 forthe upward passage of air, and a grate resting on thegrate-supporting-flange, substantially as and for the purposesdescribed.

In testimony whereof I have hereunto set my hand and aflixed my seal inpresence of two subscribing witnesses.

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